Fatigue life analysis model of crankshaft under uncertain working conditions based on physical-data collaboration

Abstract

The uncertainty of working conditions often affects the fatigue life of the crankshaft. In order to study the impact of uncertain working conditions on the fatigue life of the crankshaft, the fatigue life analysis model of crankshaft under uncertain working conditions was established based on the engine working process model, equivalent stress calculation model, fatigue life calculation model and surrogate model. The engine working process model was established based on the filling and empty method to simulate engine performance under different working conditions, and the accuracy of the model is verified by experimental data. The equivalent stress calculation model under uncertain working conditions was established by combining the performance data with the equivalent stress calculation model. Based on the fatigue life curve, the transformation from equivalent stress to fatigue life can be realized, and the fatigue life of crankshaft under uncertain working conditions can be obtained. Finally, the relationship model between working condition and fatigue life was established based on the Kriging surrogate model. Through comparative analysis, the calculation errors of the established equivalent stress calculation model and fatigue life calculation model are 2.6% and 1.9% respectively. This study not only establishes the relationship between fatigue life and working conditions of crankshaft based on physical-data collaboration, but also provides an effective model basis for follow-up crankshaft reliability analysis.